Art of predicting accurate weather
STAYING UP TO DATE Meteorologists are building robust mathematical models that consider current weather & environmental conditions. REPRESENTATIVE IMAGES
Accurate weather forecasts play a significant role in saving thousands of lives around the world. Weather, defined as the state of the atmosphere around us, is very dynamic. Hence, understanding weather is imperative to our survival and has given rise to a new branch of science called meteorology. Derived from the Greek word metérōos, the word meteorology translates to ‘the study of things in the air’.
In the Indian context, the understanding of weather has many imperatives. “For a country like India, which is primarily an agriculture-based economy, meteorology is very relevant. Monsoon rains that last for four months in a year, drive our agriculture, water requirements, and the ability to predict them becomes very critical,” says J Srinivasan, professor at the Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bengaluru. In recognition of meteorology’s importance, the United Nations’ World Meteorological Organisation observes March 23 every year as World Meteorological Day. It has declared the theme for 2017 to be ‘Understanding Clouds’.
Tracing the origins
Considered the founder of meteorology, Greek philosopher Aristotle’s work Meteorology in 350 BC describes the water cycle responsible for bringing rain. But Indian knowledge about cloud formation and rain, and the seasonal cycles dates back to the Upanishads. Varhamihira’s classical work Brihatsamhita, written in around 500 AD, provides clear evidence to the atmospheric processes that existed in those times. Similar works around the world have enriched our understanding of other atmospheric phenomena such as seasons, winds, thunder, and snow.
The 15th century marked a new era in meteorology with the invention of the first standardised rain gauge by Prince Munjong of Korea. Subsequent inventions of instruments like anemometer, thermoscope, mercury barometer and hygrometer gave us the ability to measure factors that influence weather. Various scientific theses furthered our understanding on various phenomena in the atmosphere.
In order to predict weather based on current conditions, weather observing networks were started in the 17th century. Here, data was collected at regular intervals and sent to a processing centre several miles away. The advent of telegraph enabled quick collection of weather observations from a wide area and this was used to produce maps of the state of the atmosphere for a region. In the late 19th century, many countries, including India, established national meteorological services.
The dawn of 20th century accelerated technological advancements such as weather satellites, computers and faster communication channels. They have opened up a new chapter in understanding and forecasting weather. The launch of the first successful weather satellite, TIROS-1 in 1960 by NASA, put ‘an eye in the sky’. Since then, many countries like China, India and Russia have followed suit and launched their own series of meteorological satellites.
These satellites, equipped with cameras and sensors, rotate the Earth in the north-south direction (polar orbiting) or remain stationary with respect to the rotating Earth (geostationary). Satellites can see more than just cloud systems; they can also help us paint a picture of the atmosphere. “Satellite images provide a better understanding of how precipitation occurs over the oceans, how a storm is born and moves to land, comprehending which was impossible before,” says Srinivasan.
In the 20th century, weather forecasting was increasingly being viewed as a problem in mathematics and physics that begged a solution based on calculations and the natural laws of physics, thus giving birth to numerical weather predictions. However, the sheer number of calculations involved in solving mathematical models limited its full potential until the advent of computers. Today, most meteorological organisations use supercomputers that can process tens of trillions of calculations in a second, thus increasing the accuracy of prediction.
As our understanding of the atmosphere and various factors at play increases by the day, meteorologists are building robust mathematical models that consider current weather and environmental conditions like temperature, pressure and wind to predict the future state of the atmosphere. Powered by massive computational ability, these models can now be run with increased resolutions. Simulating small-scale conditions that can catapult a routine thunderstorm or hurricane into a monster is now a simple task.
“We have moved from statistical forecasting to computer-based forecasting that involves better models which assimilate data from the satellites. Since our atmosphere is very complicated, predicting major events like cyclones, which was impractical before, is now done with no difficulty”, explains Srinivasan. Now, meteorologists make accurate predictions for the next 72 hours, and in the process, help us provide a better response to natural disasters.
The way ahead
With pioneering technologies like the Internet of Things (IoT) and Big Data what does the future of meteorology look like? “With the way things are going, I am confident that the future of meteorology would be very exciting,” opines Srinivasan. “Today, sensors are getting smaller and inexpensive, which will revolutionise data collection. The massive power of computing enables us to model complex phenomena in the atmosphere at a very low resolution.”
The field of meteorology is filled with intellectually stimulating challenges like the accurate prediction of monsoon or understanding every movement of clouds at a resolution of about a kilometre from Earth’s surface. “Challenges in this field are plenty to keep one busy for the next 50 years! Solving these challenges would yield dramatic results in the future,” remarks Srinivasan.
Humanity’s quest for decoding nature’s ways are never ending and meteorology is no exception. Our small but significant steps in understanding the enigma of weather has now armed us with information that can be the trump card against nature’s games. What can be better day than World Meteorological Day to reminisce this and hope for clues to solve a bigger challenge like the climate change.
(The author is with Gubbi Labs, a Bengaluru-based research collective)